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Late last week, California utility Pacific Gas and Electric (PG&E) asked the state to approve four lithium-ion battery storage projects. Three of which would be owned and operated by a third party, and one, built by Tesla, would be owned and operated by PG&E itself.

One of the projects—spearheaded by energy company Vistra (which recently merged with Dynegy)—could become the world's first grid-scale, lithium-ion battery installations to store more than a gigawatt-hour of energy.

Tesla's project is also huge. It would deliver 730MWh of energy, but Tesla's contract with PG&E suggests the utility could opt to increase the size of the battery to 1.1GWh.

The Tesla installation is expected to discharge 182.5MW for 4 hours (hence, the 730MWh number). But the contract could be bumped up to a discharge duration of 6 hours, which would result in just under 1.1 GWh of storage owned by PG&E. For comparison, last year Tesla completed the largest lithium-ion battery installation in the world in South Australia. That battery system clocked in at 100MW/129MWh of storage.

Storage of this size allows the utility to add more renewable energy because if wind speeds drop or cloud cover hurts solar, a battery can kick in to meet the rest of that load.

The Tesla/PG&E battery would be located at the Moss Landing substation in California, near Monterey Bay (and home to the Monterey Bay Aquarium Research Institute). PG&E said it expects the battery to be completed by 2019, pending the approval of the California Public Utilities Commission (CPUC).

Vistra/Dynegy also bid to build a 300MW battery installation that would be able to be discharged for four hours. At 1.2GWh, the battery would be among the largest in the world and would also be located at the Moss Landing site. A press release from the company projects that the installation would be completed by the end of 2020. The project would be supported by a 20-year contract with PG&E to buy energy from Vistra.

A spokeswoman for Vistra said the company had not yet selected a provider to source its batteries from. The project would use two existing interconnection points at Moss Landing to connect to the grid, as well as "an existing turbine building on the site to house the batteries."

The two other projects are smaller and include a 75MW / 300MWh battery installation from a company called Hummingbird Energy Storage LLC, as well as an aggregation project from Micronoc Inc, which will site 10MW / 40MWh of batteries at commercial locations.

These projects depend on the CPUC's approval to move forward, but the commission directed PG&E to accelerate its solicitation of battery storage in January, so the proposals aren't too surprising. A response from CPUC is expected in 90 days.

Correction: The name of the Monterey Bay Aquarium Research Institute was corrected.

Damn, that's impressive! We're getting into some serious numbers here. About damned time, too! Now I just wonder if Tesla's going to install it in what for anyone else would be an absurdly short period too, just because they can?

What sorts of fire suppression/mitigation do they generally do for those Lithium Ion battery centers? From the photo, it looks like each of the 'blocks' is self-contained. Do they have fire breaks internally that separate the battery packs? Granted, there are no hazards from punctures (except during maintenance), but a fire from overheating or some other cause could really spread fast. Much faster than with lead-acid batteries. All in all, that is an amazing amount of energy in a pretty small space...

... but Tesla's contract with PG&E suggests the utility could opt to increase the size of the battery to 1.1GWh.

... but still falls short of powering a flux capacitor.

Given the 50 msec or so of a lightning strike, I would estimate 3600x20x1.1/121 = 654 journeys through time, assuming that you can power a large enough super capacitor with no loss. Personally, I think the DeLorean is unlikely to be able to accelerate to 88 mph that number of times.

... but Tesla's contract with PG&E suggests the utility could opt to increase the size of the battery to 1.1GWh.

... but still falls short of powering a flux capacitor.

GWh is energy (joules). The Delorean requires 1.21 GW (watts aka power) to energize the flux capacitor. So you'd have to discharge that entire battery bank in 1 second to reach anywhere near that power level, which is not what it is specced for at all (so think battery fire).

... but Tesla's contract with PG&E suggests the utility could opt to increase the size of the battery to 1.1GWh.

... but still falls short of powering a flux capacitor.

GWh is energy (joules). The Delorean requires 1.21 GW (watts aka power) to energize the flux capacitor. So you'd have to discharge that entire battery bank in 1 second to reach anywhere near that power level, which is not what it is specced for at all (so think battery fire).

In one *hour*, which is only a bit over 4x the max on that Vistra installation. And generally batteries can discharge much faster than their nameplate rating for a short period. So it would probably work.

What sorts of fire suppression/mitigation do they generally do for those Lithium Ion battery centers? From the photo, it looks like each of the 'blocks' is self-contained. Do they have fire breaks internally that separate the battery packs? Granted, there are no hazards from punctures (except during maintenance), but a fire from overheating or some other cause could really spread fast. Much faster than with lead-acid batteries. All in all, that is an amazing amount of energy in a pretty small space...

Each Powerpack has 16 racks of cells, each of which should contain a fire; the unit itself is also quite fire-resistant.

They tested that quite thoroughly - while I don't much trust Electrek as a source, this particular article has an excellent series of pictures.

N.B. - the dramatic header image was produced by using a propane burner on the thing for over an hour...

What sorts of fire suppression/mitigation do they generally do for those Lithium Ion battery centers? From the photo, it looks like each of the 'blocks' is self-contained. Do they have fire breaks internally that separate the battery packs? Granted, there are no hazards from punctures (except during maintenance), but a fire from overheating or some other cause could really spread fast. Much faster than with lead-acid batteries. All in all, that is an amazing amount of energy in a pretty small space...

... but Tesla's contract with PG&E suggests the utility could opt to increase the size of the battery to 1.1GWh.

... but still falls short of powering a flux capacitor.

GWh is energy (joules). The Delorean requires 1.21 GW (watts aka power) to energize the flux capacitor. So you'd have to discharge that entire battery bank in 1 second to reach anywhere near that power level, which is not what it is specced for at all (so think battery fire).

GWh is gigawatt-hours, so the 1.1GWh installation is 10% shy of having enough storage capacity to power the flux capacitor for an entire hour!

Still, supplying that power at 6x the design power will probably mean a failure somewhere - probably the inverters converting the battery DC to grid AC. Practically all modern lithium ion batteries can be discharged in an hour (1C) without drama.

No word how long the flux capacitor needs to be supplied at that power per jump, or how many it could do in that one glorious hour.

What sorts of fire suppression/mitigation do they generally do for those Lithium Ion battery centers? From the photo, it looks like each of the 'blocks' is self-contained. Do they have fire breaks internally that separate the battery packs? Granted, there are no hazards from punctures (except during maintenance), but a fire from overheating or some other cause could really spread fast. Much faster than with lead-acid batteries. All in all, that is an amazing amount of energy in a pretty small space...

Each Powerpack has 16 racks of cells, each of which should contain a fire; the unit itself is also quite fire-resistant.

They tested that quite thoroughly - while I don't much trust Electrek as a source, this particular article has an excellent series of pictures.

N.B. - the dramatic header image was produced by using a propane burner on the thing for over an hour...

Thanks for the link, that was a pretty cool article. It's interesting that even with the propane burner, the visible fire didn't start for about 2 hours. Of course, I kept thinking that the article was a long-lost episode of Myth Busters. It had that "well, this won't blow up on its own... how can we force it to go boom?" vibe with the burner :-)

What sorts of fire suppression/mitigation do they generally do for those Lithium Ion battery centers? From the photo, it looks like each of the 'blocks' is self-contained. Do they have fire breaks internally that separate the battery packs? Granted, there are no hazards from punctures (except during maintenance), but a fire from overheating or some other cause could really spread fast. Much faster than with lead-acid batteries. All in all, that is an amazing amount of energy in a pretty small space...

Each Powerpack has 16 racks of cells, each of which should contain a fire; the unit itself is also quite fire-resistant.

They tested that quite thoroughly - while I don't much trust Electrek as a source, this particular article has an excellent series of pictures.

N.B. - the dramatic header image was produced by using a propane burner on the thing for over an hour...

Thanks for the link, that was a pretty cool article. It's interesting that even with the propane burner, the visible fire didn't start for about 2 hours. Of course, I kept thinking that the article was a long-lost episode of Myth Busters. It had that "well, this won't blow up on its own... how can we force it to go boom?" vibe with the burner :-)

I remember Tesla's early days were spent blowing up battery packs in the parking lot outside their rented garage where they hand-made Roadsters. They learned a lot about making the packs safe and venting gas and flames in a controlled way. They have tons of patents around that.

... but Tesla's contract with PG&E suggests the utility could opt to increase the size of the battery to 1.1GWh.

... but still falls short of powering a flux capacitor.

GWh is energy (joules). The Delorean requires 1.21 GW (watts aka power) to energize the flux capacitor. So you'd have to discharge that entire battery bank in 1 second to reach anywhere near that power level, which is not what it is specced for at all (so think battery fire).

GWh is gigawatt-hours, so the 1.1GWh installation is 10% shy of having enough storage capacity to power the flux capacitor for an entire hour!

Still, supplying that power at 6x the design power will probably mean a failure somewhere - probably the inverters converting the battery DC to grid AC. Practically all modern lithium ion batteries can be discharged in an hour (1C) without drama.

No word how long the flux capacitor needs to be supplied at that power per jump, or how many it could do in that one glorious hour.

... but Tesla's contract with PG&E suggests the utility could opt to increase the size of the battery to 1.1GWh.

... but still falls short of powering a flux capacitor.

GWh is energy (joules). The Delorean requires 1.21 GW (watts aka power) to energize the flux capacitor. So you'd have to discharge that entire battery bank in 1 second to reach anywhere near that power level, which is not what it is specced for at all (so think battery fire).

GWh is gigawatt-hours, so the 1.1GWh installation is 10% shy of having enough storage capacity to power the flux capacitor for an entire hour!

Still, supplying that power at 6x the design power will probably mean a failure somewhere - probably the inverters converting the battery DC to grid AC. Practically all modern lithium ion batteries can be discharged in an hour (1C) without drama.

No word how long the flux capacitor needs to be supplied at that power per jump, or how many it could do in that one glorious hour.

If they force you to buy it and also help pay for it, its good to be the seller.

I hope the actual legislation was smart enough to spell out MWh targets and not just MW targets.

What legislation?

This is an energy contract proposal by the energy company looking for contractors to fulfill the specifications, and Tesla's response won. The energy company is regulated by the state, which means any new projects have to be presented in full, with all the details, including who would do it, to the regulators for final approval. Often times, the regulators are those who ask the energy company to come up with a plan. Other times, the energy companies have to go to the regulators to seek approval to research things for projects the energy company feels it needs.

If approved by the regulators, it gets financing. If it's not, the energy company can re-vamp the proposal, do new bids and submit what they get for another look, or just drop the idea.

Regulators have the final say on what gets done, since it's going to be state-supported in some fashion along the line.

Vistra seems like the real deal in this space, although it seems likely they might end up purchasing Tesla/Panasonic cells.

Speaking of which, who does Tesla use for their actual utility install? Doesn't seem like the kind of expertise they would retain in-house, more likely a closely involved subcontractor. Although after this they may be expanding this part of the business.

I can't find any public info on Hummingbird, wonder if it's a LLC for a bigger player or a Whitefish type scenario with two employees and an office until they got this bid.

Ars, hope there is followup on this project, which seems really important to a renewables revolution in energy.

What’s the back story in PG&E wanting to put 500 MW of batteries at Moss Landing?

Nice place for bird watching, but apart from that...

Looks to me like that is (or was) the location of a power plant. Putting batteries where there's already power lines and transformers makes a lot of sense.

They should install some at San Onofre, as well, since PG&E decommissioned the nuclear power plant (and then billed the customers for it, despite the fact that the customers were totally against both the decommissioning and being charged for it.)

What sorts of fire suppression/mitigation do they generally do for those Lithium Ion battery centers? From the photo, it looks like each of the 'blocks' is self-contained. Do they have fire breaks internally that separate the battery packs? Granted, there are no hazards from punctures (except during maintenance), but a fire from overheating or some other cause could really spread fast. Much faster than with lead-acid batteries. All in all, that is an amazing amount of energy in a pretty small space...

Very valid point. The fire hazard is the main reason lithium battery storage is hitting major opposition from residents in wildfire zones. I don't really understand why not simply use lead acid batteries? It's not like weight is an issue in stationary situations.

Lead acid batteries have maintenance. They are absolutely a fire hazard of the first degree. They can go off like a bomb. I remember from my forklift days this maintenance was only done when we absolutely had to. Which is weekly. It involves battery acid testing, and scary high amperage. The acid is tested with this tubes with little balls in it. Nasty stuff. Have to pull a bit from every cell. Your wedding ring could kill you sort of thing even with just the difference between cells ( ? may have been just 12v cell to cell, but accidentally short one and they would flash heat from the amps and go boom ). End to end the pack could fry you crisp ( thinking it was 270v DC with a very high amperage rating ).

What sorts of fire suppression/mitigation do they generally do for those Lithium Ion battery centers? From the photo, it looks like each of the 'blocks' is self-contained. Do they have fire breaks internally that separate the battery packs? Granted, there are no hazards from punctures (except during maintenance), but a fire from overheating or some other cause could really spread fast. Much faster than with lead-acid batteries. All in all, that is an amazing amount of energy in a pretty small space...

Very valid point. The fire hazard is the main reason lithium battery storage is hitting major opposition from residents in wildfire zones. I don't really understand why not simply use lead acid batteries? It's not like weight is an issue in stationary situations.

What sorts of fire suppression/mitigation do they generally do for those Lithium Ion battery centers? From the photo, it looks like each of the 'blocks' is self-contained. Do they have fire breaks internally that separate the battery packs? Granted, there are no hazards from punctures (except during maintenance), but a fire from overheating or some other cause could really spread fast. Much faster than with lead-acid batteries. All in all, that is an amazing amount of energy in a pretty small space...

Very valid point. The fire hazard is the main reason lithium battery storage is hitting major opposition from residents in wildfire zones. I don't really understand why not simply use lead acid batteries? It's not like weight is an issue in stationary situations.

Lots of reasons but the primary one is charge/discharge efficiency is absolute crap. You end up wasting a lot of energy which is something a grid operator doesn't want to do.

Also to have any longevity to speak of you can't discharge very low. 50% depth of discharge is about as low as you can go and even that will kill batteries quick. 20% depth of discharge is more common. So 5 kWh = 1 kWh usable. Suddenly lead acid doesn't look so cheap when you comparable usable capacity over the same lifespan instead of nominal capacity.

Lithium ion is simply superior in every possible metric. It is cheaper, it last longer, and it is more efficiency roundtrip. The question you should ask is why would someone want to pay more for a less efficient and shorter lived lead acid battery station?

What sorts of fire suppression/mitigation do they generally do for those Lithium Ion battery centers? From the photo, it looks like each of the 'blocks' is self-contained. Do they have fire breaks internally that separate the battery packs? Granted, there are no hazards from punctures (except during maintenance), but a fire from overheating or some other cause could really spread fast. Much faster than with lead-acid batteries. All in all, that is an amazing amount of energy in a pretty small space...

Very valid point. The fire hazard is the main reason lithium battery storage is hitting major opposition from residents in wildfire zones. I don't really understand why not simply use lead acid batteries? It's not like weight is an issue in stationary situations.

Lead acid batteries have maintenance. They are absolutely a fire hazard of the first degree. They can go off like a bomb. I remember from my forklift days this maintenance was only done when we absolutely had to. It involves battery acid testing, and scary high amperage. Your wedding ring could kill you sort of thing even with just the difference between cells ( ? may have been just 12v cell to cell, but accidentally short one and they would flash heat from the amps and go boom ). End to end the pack could fry you crisp ( thinking it was 270v DC with a very high amperage rating ).

Lead-acid had a potential of 2 volts per cell, and auto-sized lead acid batteries will have between 3 and 24 cells, for 6-48 volts.

Current (amperage is a measure of current) is largely a function of voltage and the resistance of the entire load, including the battery. And yes - 270 volts is absolutely enough to kill a person by stopping their heart.

However, my reading suggests that most electric forklifts are 36 or 48 volts. 270v seems like a high number, especially for a hydroelectric device like a forklift.

What sorts of fire suppression/mitigation do they generally do for those Lithium Ion battery centers? From the photo, it looks like each of the 'blocks' is self-contained. Do they have fire breaks internally that separate the battery packs? Granted, there are no hazards from punctures (except during maintenance), but a fire from overheating or some other cause could really spread fast. Much faster than with lead-acid batteries. All in all, that is an amazing amount of energy in a pretty small space...

Very valid point. The fire hazard is the main reason lithium battery storage is hitting major opposition from residents in wildfire zones. I don't really understand why not simply use lead acid batteries? It's not like weight is an issue in stationary situations.

Lots of reasons but the primary one is charge/discharge efficiency is absolute crap. You end up wasting a lot of energy which is something a grid operator doesn't want to do.

Also to have any longevity to speak of you can't discharge very low. 50% depth of discharge is about as low as you can go and even that will kill batteries quick. 20% depth of discharge is more common. So 5 kWh = 1 kWh usable. Suddenly lead acid doesn't look so cheap.

Lithium ion is simply superior in every possible metric. It is cheaper, it last longer, and it is more efficiency roundtrip. The question you should ask is why would someone want to pay more for a less efficient and shorter lived lead acid battery station?

If for some reason an alternate chemistry is required, salt water flow batteries would be way better than Pb batteries. They take up lots of space - you need about 3.5 million cubic feet for a 700 MW battery, but if you have an empty salt mine just laying around...

Each Powerpack has 16 racks of cells, each of which should contain a fire; the unit itself is also quite fire-resistant.

Tesla's safety features ensure the cell will not "explode" but it doesn't do anything to prevent a fire.

The only way to "contain" this type of fire is to wait for it to finish on it's own, which takes about 4 hours in this case according to testing (that's good, electric cars can burn for several *days*).

During those hours, the cell will be hot enough to cause thermal run away every other nearby cell, so all 16 cells will be destroyed if one of them starts burning.

In the photos (which aren't the plant in this article, since it hasn't been built yet), it looks like the towers are close together meaning you're guaranteed to lose many towers if a fire starts.

That would be a risk they've decided to take — simply having some clear space between towers would prevent a fire from spreading. But having clear space between every tower is also expensive - maybe more than the insurance to cover a fire.

The spread of fire can be slowed down by spraying insulating foam over it — this is what battery-transport aircraft use if a fire starts in mid flight. In this case it could give you enough time to uninstall other battery towers that aren't yet hot enough to start burning, assuming you have cranes on site and staff trained to deal with the situation quickly.

"you're guaranteed to lose many towers if a fire starts." citation required.